Slideshow: Vehicle-to-Grid Technology Gains Momentum

Electric car batteries can do more than power electric cars. They can send current to homes and buildings, or send it back to the grid when demand is high. Some experts even believe EV batteries might one day boost the prominence of renewables by storing the energy from wind and solar farms.

The idea of so-called "vehicle-to-grid" schemes inevitably stirs debate among engineers. But make no mistake: The concept has a huge following. Googling the term "vehicle-to-grid" yields an astounding 526 million hits. That's one reason electric utilities, auto manufacturers, and university researchers are all studying the concept.

Click here to read the rest of the story at Design News and see photos and diagrams from ongoing vehicle-to-grid programs.

Willett Kempton of the University of Delaware has been a driving force behind the idea of vehicle-to-grid (V2G) technology. In 2013, Delaware teamed with NRG Energy to launch the world's first revenue-generating V2G project. Here, Kempton is shown with a Honda Accord Plug-In Hybrid that's being used as part of a demonstration project by the university.
(Source: Honda)

They say that the additional costs are not that high (but I did not verify that myself). Nowadays so-called "plug in hybrids" are gaining popularity. In these cars can the battery be charged at home. The charger used for this is now being expanded to enable bidirectional operation: so it can charge the car but can also be used to power the house from the car's battery if necessary.

I think this is a very important idea. Power plants at present have no means to predict power useage five minutes into the future. So they run at excess capacity all the time, probably at the 20-30% rate above present demand. Since there is no way to store bulk electricity, the electricity is unused--just a waste of coal. Similarly, windmill generators must have (usually) coal power plant backup power running just in case the wind stops for an instant.

If power plants could run at 105% of demand with distributed batteries taking peak load for a few minutes of each hour, we solve the electricity storage problem.. and save a lot of coal.

Okay...that makes sense. In emergency blackout scenario providing power from the car battery to home or to grid sounds reasonable for places like Japan. Thank you for the insight. Again a question that comes to my mind, is the cost of these equipments which would convert the battery power to grid/home would be low enough justiifying "rarely-in-use" utility? I am sure it does as these great companies are into these business...but just wanted to find a justification for my satisfaction.

The slide show indeed shows Nissan as example. However, also Mitsubishi and Toyota offer similar systems. As was already noted, is this mainly targeted at the situation in Japan where power may be disrupted due to earthquakes. In this context should "vehicle-to-grid" also be seen as "your vehicle to your house". It is more targeted at using the energy from your car's battery to your own house. Delivering energy from your car to the entire grid is another step, involving some other hurdles.

If batteries were a practical way to deal with peak loads, the power companies would be using them already.

Hiding the cost by using electric car batteries makes no sense at all. The silly person that would let the grid cycle his battery into premature failure is also the sort of person that believes that electric cars are practical. Neither electric cars nor batteries can seriously compete with a VW diesel that gets 60 mpg and simply does its job.

As much as we would all love to have practical electric cars, wishing does not make it so. Cars exist to fulfill a practical purpose, thus they must be practical.

People generally don't recognize how remarkable the performance of a car with an internal combustion engine is. You squeeze the trigger on the hose for a few minutes and enough energy pours into the car to propel it 400-600 miles down the road at 70 mph in comfort on a cold snowy day and it will do it every day, all day long. The Chevy Volt gets 40 miles on a cold day with the electric heat on.

Regrettably, there is no electric car battery that can even begin to compare to the most ordinary internal combustion engine - and none in sight.

Here V2G is under research project, and centre of focus is Hybrid Vehicle not pure EVs, you are right in case of pure EVs it require power from Grid to charge the vehicle, but in case of hybrid vehicles one can easily use the power stored in batteries to other purposes.

Since Japan is dissater prone. The idea is to have Leaf as back-up power source in case of power outage. If thing happened they just cut power usage to lighting and radio/tv for news and information for a night and still have enough power left in Leaf to avac. the next morning, which I think quite a briliant.

The major concern for the batteries used in EVs , is the capacity to provide long range for highway driving, and quciker charging time.

Unless these criterion are met , how can these batteries be supplying prower to the grid - I somehow do not understand.

But connectivity with the grid can have one advantage. These EVs connected to the grid can actually draw the power from the grid when needed and return the power to the grid say while braking or while driving downhill.

Going through the slides I learned that Nissan engineers believed that a 24-kWh Leaf battery could power an average Japanese household for about two days (assuming 10-12KWh consumption per day). But again, I would agree with some of the comments posted for this article in designnews that why would a person want to sell electric power from his/her EV, unless the incentives are great, which I doubt would justify the long duration taken to charge the battery. Will this be practical?